This invention relates to portable abrading tools including a shoe carrying a sheet of abrasive material, such as sandpaper, to be utilized in performing a work abrading operation.
In conventional portable sanding tools, one of the most common methods of attaching the sandpaper to a shoe of the tool has been by the use of spring clips attached to the upper side of the shoe at its opposite ends. These clips are manually actuable to a released position in which they allow reception of an end of the sandpaper sheet adjacent or in engagement with the clip, following which the clip is released to return by spring force to an active position in which it grips the paper tightly and retains it against detachment from the shoe. Numerous variations of these spring clip retaining units have been proposed and utilized in the past, but in each the manual manipulation of the clips has entailed some inconvenience and more expenditure of time than would be desired upon each change of paper, and in many instances the ultimate retention has been of less than optimum effectiveness. Some typical examples of prior manually actuable spring clips of this general type are found in U.S. Pat. Nos. 2,509,561, 2,639,564, 2,683,337, 2,735,241, 2,848,850, 2,893,174, 3,183,638, 3,267,622, 3,349,523 and 3,546,822.
Another prior arrangement for detachably securing a sheet of abrasive material to a sander shoe is by use of an adhesive material between the paper and the underside of the shoe, which material may be a layer of pressure sensitive adhesive carried by the back side of the sandpaper sheet and adapted to adhere to the undersurface of a cushion, and after use be stripped from that undersurface for replacement by another self-adhesive sandpaper sheet. In my prior U.S. Pat. No. 3,892,091, I have disclosed an arrangement utilizing such a self-adhesive sheet of abrading material which extends along and is adhered to the undersurface of the shoe and at the forward end of the shoe extends upwardly and then rearwardly into a locating recess formed at the upper side of the forward portion of the shoe. This locating recess is of fixed dimension, and coacts with the adhesive attachment of the sheet to provide a combined retention system for holding the forward portion of the sheet in a position of extension about the forward portion of the shoe.